Molded knob



March 3, 1931. D. R. PARKS MOLDED KNOB Fi l ed March 27. 1928 &

Dfln/e/ A ORNEY lNYENTOR 7?. Parks Patented Mar.'3, 1931 DANIEL R.PAnKs, or :eoon'ron, New JERSEY MOLDED KNOB.

Application filed March 27, 1928. Serial in). mm.

. because of their light weight, since gear shift levers reflect orrespond to the vibrations of the car in which they are mounted likeinverted pendulums, and this effect is decreased as the weight of theball is lessened.

By the term resinoid is intended that type of synthetic product which inits initial condition or A stage is fusible and soluble, but istransformable to an infusible insoluble condition or C stage uponapplication of heat. As supplied to the molder, the resinoid content ofthe composition is in the A stage to the extent that it fuses and flowswhen heat is first applied, but continued heating soon causes thetransformation to the C stage. This plastic and hardening nature of theresinoid molding composition and other properties, particularly that ofshrinkage during a molding operation, present problems as to disposal ofthe material and provision for adequate contact with the metallic memberto which it is to be attached. Experience has shown in the molding ofsolid balls: or knobs, that distortion from shrinkage is so apt to occurthat, if threads are molded therein for engagement with a metallicmember, retapping is generallynecessary; consequently it has beenregarded as better practice to supply metal inserts as the attachingmeans. These, however, add materially to the cost as they requirepreliminary machine, knurling, etc., and furthermore they complicate themolding operation, for such inserts must be firmly anchored to avoiddisplacement when molding pressure is applied.

Inserts-have the additional undesirable effeet that they add verymaterially to the weight of a knob molded from resinous compositions andthereby the response to the ear vibrations is markedly increased.

In accordance with the present invention, articles are molded fromcompositions containing phenolic condensation products with the absenceof metallic or other inserts and furthermore with economy in the'use ofthe compositions, while securing articles of pleasing appearance andrequisite configuration.

the drawings which illustrate mer ts of the invention: I I

Fig. 1 is a view in elevation of a knob shown partly in section andmounted upon a gear shiftiever'provided with a shoulder;

Fig. 2 is a plan'view of the top member of the knob; and b Fig.3 isa'view in elevation and partly in section of a modified form of knobmounted on a gear shift lever without a shoulder.

The knob is preferably composed as two members, an upper concave-convexmember 10 and a lower cup-shaped member 11, having walls 12, 13 "ofsubstantially uniform thickness. The upper member is provided withanaxially extending integral and centrally disposed sleeve or socket 14Eprojecting from the interior surface and whose wall is substantially ofu'niformthickness approximating that 'ofthememberi The socket is castwith an internal thread'15.

The lower cup-shaped member 11 has a thickened central portion 16through which extends an aperture 17. The upper edge 18 of'the member isrecessed asat 19, and the lo wer'edge'of the upper member has aperiplierallip 21 adaptedto fit the recess 19 The opening 17 maybe'provided with an internal thread 22 as shown in the modified form ofFig. 3. V Y hen the parts of the knob are assembled, the opening 17 isin alignment with the, socket embodi- 14 and the lip 21 fits into therecess '19. If the lever to which the knob is attached, has a shoulder23 to contact the member, as shown in Fig. 1, it is not necessary thatthe opening 17 be threaded. Inthis case the threaded end 24 of the leveris engaged by the socket '14 and the lower member is thus forced againstthe shoulder. The socket is preferably made long enough to subtendsubstantially the space enclosed by the members when assembled and thusgive extended contact with the lever. Preferably, however, contact withthe lower member is avoided so that, as the upper mem ber is turned uponthe lever and thereby drawn against the lower member, the members areslightly sprung through their contacting rims or edges and thus arelocked to each other and to the gear shift lever.

With the lower member threaded onto the lever as in Fig. 3, a lock nutaction is secured when the upper member is screwed down upon the lowerone.

Members having the configuration as above described can be molded withthe threads cast in the socket and without requiring any metal insert.This may be ascribed to the hollow construction and to the substantiallyuniform thickness of the socket whereby all parts shrink at equal ratesand distortion is thereby avoided. In actual operation it is found thatsuch members can be molded with a threaded pin fitted within the mold toform the internal threads of the socket; and upon opening of the moldparts, the molded article is readily removed by unscrewing it from thepin while warm. The molded member does not perceptibly distort uponcooling and it can be attached to a gear shift lever without thenecessity of any further operations upon it.

Likewise the molding of the threaded aperture in the lower or cup-shapedmember is effected by inserting a threaded pin in the mold from whichthe molded part is removed by unscrewing. Any shrinkage of the materialduring cooling is uniform so that no dliosltortion of the tappedaperture is noticea e.

The description and illustrations given are specific to gear shift leverknobs. It is evident, however, that molded knobs made in ac cordancewith this invention, are adapted for other uses. Furthermore, whilecompositions of the resinoid type have been specified and are preferred,other moldable plastic materials, including those containing naturalresins or gums, as, for example, shellac, can be substituted. It is tobe understood, therefore, that the invention is not restricted to i hespecific use or composition given, but is to be accorded a scopecommensurate with the appended claims.

I claim:

1. As an article of manufacture a hollow knob molded from a phenolicresinoid compo sition for attachment to the threaded end of an elongatedmetallic rod and comprising a concave convex member having an axiallyextendingintegral socket projecting from its interior surface, saidsocket having an internal thread cast therein, a cup-shaped member witha thickened central portion having an aperture therethrough cast with aninternal thread, said cup-shaped member having a recess cast in the rim,and a lip extending from the edge of the concave-convex member forengaging said recess, said socket having a length sulficient to extendwithin, but not to contact the cup-shaped member when assembled, wherebya spring locking action can be secured when the members are attached tothe rod.

2. As an article of manufacture a hollow knob molded from a resinoidcomposition and comprising a concave convex member having a threadedsocket molded integrally therewith, and a cup-shaped member contactingwith said concave-convex member and having a threaded aperture inalignment with said socket whereby, when assembled upon a threaded rod,one member serves as a lock nut for the other member.

In testimony whereof I affix my signature.

DANIEL R. PARKS.

